KamiKowa: That Time I Got Transmigrated With A Broken Goddess - Chapter 7: [] Rerolls! Rerolls! Rerolls!

The world was never the same after that day.Humanity learned that they weren't alone in the universe, but that wasn't something they had the time to worry about.Their realization was accompanied by catastrophe.Creatures beyond their wildest imaginations poured down from the sky and appeared from the earth. They slaughtered humans as if it was their singular purpose, driving them to the brink of extinction.The people of the world did everything in their power, developing unique traits and technologies to create a united front their enemies couldn't penetrate.They secured victories and repopulated, feeling as if they stood a chance against the foreign invaders.They fought and they fought, doing everything they possibly could to ensure their survival.Until the Great Calamities appeared.In front of them, humanity was nothing regardless of its efforts.One by one, the worlds were turned into piles of rubble in between the cracks of their teeth. Civilization was torn apart, and the evolved humans living within could do nothing to stop its collapse.Humanity itself was left extinct, and in the end, only a single man was left alive amidst the chaos.Why?For what reason were they punished so?Nobody knew why the attacks began in the first place.He looked into the distance at the memories of the past and firmed his resolve.“It can only be me.”He knew of a miracle that could return him to the place of those memories.He knew of a way to make the wheels of time spin in reverse.And using it, he alone would save humanity from its doomed fate.That was his sacred duty as its final survivor.

I lived for you in the last lifetime, everything I did was for you, yet you wanted me to die; so, this time, life is mine to live! This world lied to me, betrayed me, and humiliated me, and I am back to change everything!

- Description from Novelupdates

There was a Senior Brother and a Junior Sister. One of them was transmigrated to this world and had cheats while the other was the reincarnation of a Great Emperor.